package/systemd: now needs target and host gcc >= 8

Since the bump of systemd from 254.13 to 256.4, systemd no longer
builds with gcc <= 7:

../src/basic/mountpoint-util.c: In function ‘fstype_is_api_vfs’:
../src/basic/macro.h:385:79: error: expected ‘}’ before ‘__VA_OPT__’
         for (typeof(entry) _va_sentinel_[1] = {}, _entries_[] = { __VA_ARGS__ __VA_OPT__(,) _va_sentinel_[0] }, *_current_ = _entries_; \
                                                                               ^

This first error is due to upstream commit
dc571cccd75db7be49b2aada64baf92e3a498c39 ("macro: terminate the
temporary VA_ARGS_FOREACH() array with a sentinel"), which was made to
support GCC 14.x. If we revert this commit, then this particular issue
goes away with GCC 7.x, but then it fails with another fairly similar
issue elsewhere:

../src/shared/varlink-idl.h:110:41: error: implicit declaration of function ‘__VA_OPT__’; did you mean ‘__TA_IBIT__’? [-Werror=implicit-function-dec
laration]
                 .fields = { __VA_ARGS__ __VA_OPT__(,) {}},              \
                                         ^

This code was added by upstream commit
e50b2a93d66eff9b41999d38b8ed5eb647e2d74c ("varlink: add
IDL/introspection logic").

Upstream commit dc571cccd75db7be49b2aada64baf92e3a498c39 first
appeared in v256, while e50b2a93d66eff9b41999d38b8ed5eb647e2d74c first
appeared in v255.

Considering systemd usual policies with the support of "old" things,
it's fairly unlikely that they will care about building with older gcc
versions. They even document in
https://github.com/systemd/systemd/blob/main/README that they need gcc
>= 8.4, so let's follow that.

Fixes:

  http://autobuild.buildroot.net/results/53c1a79c391e3cc7c230017853ba935202c8d20d/

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/systemd/Config.in

@@ -23,8 +23,8 @@ menuconfig BR2_PACKAGE_SYSTEMD
 	depends on BR2_TOOLCHAIN_USES_GLIBC
 	depends on BR2_TOOLCHAIN_HAS_SSP
 	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_15
-	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5
-	depends on BR2_HOST_GCC_AT_LEAST_5 # host-systemd
+	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_8
+	depends on BR2_HOST_GCC_AT_LEAST_8 # host-systemd
 	select BR2_PACKAGE_HAS_UDEV
 	select BR2_PACKAGE_DBUS if !BR2_PACKAGE_DBUS_BROKER # runtime
 	select BR2_PACKAGE_LIBCAP

package/systemd/Config.in.host

@@ -1,4 +1,4 @@
 # Select this if you need host systemd tools (e.g. systemctl)
 config BR2_PACKAGE_HOST_SYSTEMD
 	bool
-	depends on BR2_HOST_GCC_AT_LEAST_5
+	depends on BR2_HOST_GCC_AT_LEAST_8

system/Config.in

@@ -126,20 +126,20 @@ config BR2_INIT_SYSTEMD
 	depends on BR2_TOOLCHAIN_HAS_SSP
 	depends on BR2_TOOLCHAIN_HAS_THREADS
 	depends on BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_15
-	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_5
-	depends on BR2_HOST_GCC_AT_LEAST_5
+	depends on BR2_TOOLCHAIN_GCC_AT_LEAST_8
+	depends on BR2_HOST_GCC_AT_LEAST_8
 	select BR2_ROOTFS_MERGED_USR
 	select BR2_PACKAGE_SYSTEMD
 	select BR2_PACKAGE_SKELETON_INIT_SYSTEMD if BR2_ROOTFS_SKELETON_DEFAULT
 
-comment "systemd needs a glibc toolchain w/ SSP, headers >= 3.15, host and target gcc >= 5"
+comment "systemd needs a glibc toolchain w/ SSP, headers >= 3.15, host and target gcc >= 8"
 	depends on BR2_PACKAGE_SYSTEMD_ARCH_SUPPORTS
 	depends on BR2_USE_MMU
 	depends on !BR2_TOOLCHAIN_USES_GLIBC || \
 		!BR2_TOOLCHAIN_HAS_SSP || \
 		!BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_15 || \
-		!BR2_TOOLCHAIN_GCC_AT_LEAST_5 || \
-		!BR2_HOST_GCC_AT_LEAST_5
+		!BR2_TOOLCHAIN_GCC_AT_LEAST_8 || \
+		!BR2_HOST_GCC_AT_LEAST_8
 
 comment "systemd highly recommends Linux >= 4.15"
 	depends on BR2_INIT_SYSTEMD